Medical Malpractice
Cord blood gas analysis determines the fetal metabolic condition when umbilical circulation stops during childbirth.
Clamping the umbilical cord is standard procedure when a baby is born. Studies have shown that this is vital to determining the baby’s health.
Umbilical cord blood gas analysis helps doctors detect if the child suffered a birth injury during delivery. Cord blood gases show whether or not a baby is experiencing acidosis, which can indicate that there was a hypoxic-ischemic event.
The results from cord blood gases are frequently used as evidence in medical malpractice lawsuits by both attorneys and doctors as a marker for the harm done to the child and to prove whether negligence was involved in a child’s injury.
When our birth injury lawyers are discussing a new case that has come into our office, one of the first questions is about the child’s cord blood gas values. But you do not need to have a malpractice lawsuit to want to understand your child’s blood gas values better and what they mean.
If you have a potential birth injury lawsuit anywhere in the United States, call us at 800-553-8082 or get an online case review.
What Are Cord Blood Gases?
To understand what cord blood gases are, it’s helpful to know how the placenta supplies oxygen and nutrition to a baby in the womb. A fetus relies on the mother for oxygen and carbon dioxide exchange. A developing baby does not breathe like it would after birth.
The placenta uses gas exchange to supply the fetus with oxygen that comes from the mother’s blood. After the mother’s blood is oxygenated, it is absorbed by the placenta’s capillaries.
The capillaries will then deliver the blood to the placenta’s main artery, which is finally transferred to the baby.
Arterial vs. Venous Cord Blood Gases
Cord blood can be taken from both the umbilical artery and vein. The arterial sample usually tells doctors more about the baby’s condition at birth because it reflects blood returning from the baby to the placenta. Venous blood reflects more of what was happening on the placental side.
Why Are Cord Blood Gases Important to Assess a Newborn?
When the baby is born, the umbilical artery briefly retains information about the baby’s condition, referred to as blood cord gases. Doctors clamp the umbilical cord within seconds after birth to measure acidity inside the umbilical artery.
The question is how much oxygen the baby was getting. Analyzing cord blood gas levels is often the best indicator of hypoxia or ischemia during delivery.
Cord gas interpretation can show how healthy the baby is and determine whether it has a birth injury.
Accurate results are also essential. This is why the cord must be clamped quickly. Waiting even 45 seconds will skew the results due to chemical changes in the artery.
What Does Low Arterial Cord Base Excess Mean?
A low arterial cord base excess, or a high base deficit, can indicate metabolic acidosis. The base deficit is calculated using measured blood levels for acid (pH), dissolved carbon dioxide gas (PCO2), and bicarbonate HCO. It is these values that describe the baby’s metabolic state.
How Do You Draw Umbilical Cord Blood?
The doctor clamps the umbilical cord quickly after childbirth. A needle withdraws blood from the cord. Again, this must be done quickly to get reliable umbilical cord blood gas results.
How Are Blood Cord Gases Measured?
The most critical measurements in arterial cord blood gas examination are the baby’s pH levels and base deficit. Both are used to determine the acidity level in the umbilical cord.
The levels determine if the baby has acidosis, a condition caused by the overproduction of acid in the blood. Acidosis usually presents itself as decreased blood pH and increased base deficit. If a baby has acidosis, you will see poor cord gases at birth. It is a red flag that indicates the presence of hypoxia during delivery.
What Are Normal Arterial Cord Blood Gas Values?
Cord blood interpretation can be complex. But these baseline values give you some indication of where there could be a problem.
Normal arterial blood cord gas values in a full-term newborn:
| Parameter | Value | Units |
| Mean pH | 7.28 ± 0.07 | N/A |
| Mean PCO2 (carbon dioxide) | 49.9 ± 14.2 | mmHg |
| Mean PO2 (oxygen) | 23.7 ± 10.0 | mmHg |
| Mean base deficit | -3.6 ± 2.8 | mmol/L |
Normal blood cord gas levels in a preterm newborn are similar but different:
| Parameter | Value | Units |
| Mean pH | 7.29 ± 0.07 | |
| Mean PCO2 | 49.2 ± 9.0 | mmHg |
| Mean PO2 | 23.6 ± 8.9 | mmHg |
| Mean base deficit | -3.3 ± 2.4 | mmol/L |
All values are ± 1 standard deviation. The “P” in PO2 and PCO2 means “partial pressure, ” which is how the cord blood gases are measured. PCO2 measures the amount of carbon dioxide gas dissolved in the blood, and PO2 measures the amount of oxygen in the blood.
Why Are PH Levels Important?
Cord pH provides a critical measurement of the baby’s acid-base status when the cord is cut. This gives a good window into the fetus’s oxygenation status in the immediate period leading up to delivery.
A normal arterial pH in a newborn suggests adequate oxygenation and perfusion during labor and delivery. Conversely, a low pH (acidosis) can indicate that the baby experienced hypoxia (reduced oxygen supply) or ischemia (reduced blood flow) at some point before, during, or after delivery.
The data shows that pH levels at birth are pretty good – but not perfect at predicting how well the child does. Severe acidosis is associated with higher risks of neonatal morbidity, such as neurological impairment, and in severe cases, mortality. Monitoring pH can help identify newborns at risk of adverse outcomes, allowing for timely intervention and close monitoring.
Remember that cord blood gas analysis is safe for the child.
How to Interpret PO2 Levels?
A PO2 level at birth can be an essential indicator in neonatal care. The partial pressure of oxygen in the arterial cord blood reflects the amount of oxygen in the blood at birth. This measurement is taken from the umbilical cord immediately after delivery.
PO2 is typically assessed as part of a larger arterial blood gas (ABG) analysis, which will also include pH, carbon dioxide pressure (PCO2), bicarbonate (HCO3), and base excess. This comprehensive approach helps assess respiratory and metabolic function in the newborn.
What Does a High Arterial Cord PO2 Mean?
A high PO2 in arterial cord blood has to be interpreted carefully. Cord blood normally has a much lower PO2 than arterial blood measured after breathing has begun. An unexpectedly high cord PO2 can sometimes raise a question about whether air entered the blood sample or whether the sample was actually arterial.
This is one reason doctors do not interpret PO2 by itself. The pH, PCO2, base excess or deficit, whether the sample was arterial or venous, and the baby’s condition at birth all matter.
What Does a Low Arterial Cord PO2 Mean?
A low PO2 can be evidence that the baby had reduced oxygen levels before birth. But cord arterial PO2 is normally low compared to blood oxygen levels after birth, so a low number does not by itself establish hypoxia or a birth injury.
Like any other test on a newborn, PO2 levels must be interpreted in the context of the baby’s overall condition and the rest of the cord blood gas results.
What Does a High Venous Cord PO2 Mean?
Venous cord blood normally has a higher PO2 than arterial cord blood because the umbilical vein carries oxygenated blood from the placenta to the baby. A high venous PO2 should therefore be compared with venous, not arterial, reference values.
How to Interpret Cord Blood PCO2 Levels
What Does a High Arterial Cord PCO2 Mean?
PCO2 measures carbon dioxide in the cord blood. Arterial PCO2 is normally higher than venous PCO2. A high arterial PCO2 can contribute to a low pH and may indicate respiratory acidosis, but it does not by itself prove that the baby suffered a hypoxic injury.
Doctors look at PCO2 together with pH, base deficit, PO2, whether the sample was arterial or venous, and the baby’s condition at birth.
What Does a High Venous Cord PCO2 Mean?
Venous PCO2 is normally lower than arterial PCO2. A high venous PCO2 has to be interpreted along with the paired arterial sample, pH, base deficit, PO2, and the baby’s condition at birth.
How Does Acidosis Affect My Baby?
Acidosis has two different types: respiratory acidosis and metabolic acidosis. Respiratory acidosis refers to high acid levels caused by impaired lung function, leading to retained carbon dioxide in the lungs and bloodstream.
Metabolic acidosis occurs when acid builds up in the body, often because inadequate oxygen delivery causes lactic acid to accumulate. Both forms of acidosis can cause neurological issues that can be temporary or permanent, depending on the severity of the damage. In general, however, metabolic acidosis is associated with more adverse outcomes.
How do you calculate acidosis? Low blood pH and high base deficit indicate acidosis, which can be calculated from pH, CO2 pressure, and hemoglobin levels.
Low pH levels caused by acidosis can result in hypoxic-ischemic encephalopathy, periventricular leukomalacia, seizures, brain hemorrhages, and cerebral palsy. In severe cases of metabolic acidosis, it can lead to multi-organ failure and even death.
The primary cause of acidosis is insufficient oxygen from the placenta to the baby.
Blood Cord Gases in Medical Malpractice Lawsuits
Blood cord gas results can be used as an essential piece of evidence in birth injury litigation. If a baby suffered from hypoxia that resulted in a birth injury, the blood cord gases can prove the legitimacy of the plaintiff’s claim.
Malpractice lawyers and medical experts can also interpret blood cord gas levels to show the severity of damage during delivery by citing the specific pH and base deficit levels.
However, doctors can also use blood cord gases to defend against birth injury lawsuits as well. If the baby has a birth injury but their blood cord gases come back normal, the obstetrician can use the umbilical cord gas levels as evidence that the injury did not occur during delivery and was not caused by negligence.
There are many reasons why a baby would have normal blood cord gases despite suffering from a hypoxic brain injury. The baby might have had poor circulation and perfusion shortly before being born, or they could have experienced a physical head injury during delivery.
There may have been an error in storing and analyzing the blood. According to one study, up to 19% of blood cord gas samples are invalid due to human error. There are also blood cord gas interpretation errors that inflate or deflate the child’s hypoxia at birth.
A medical malpractice attorney must be skilled in medical knowledge about pH and base deficit levels to prevail in a birth injury lawsuit involving blood cord gases.
They should take the time to examine the process of taking blood cord gas samples and identify any possible technical errors that make the results invalid. Birth injury lawyers also need to work closely with a medical expert to prove the cause and timing of the birth injury.
Do Abnormal Cord Blood Gases Mean My Child Has a Brain Injury?
Abnormal cord blood gas results are a marker for a birth injury. But abnormal fetal cord blood gas results do not mean that your child has a brain injury. Many children with troubling cord blood gas and APGAR results have no long-term physical or cognitive deficits.
Hiring a Birth Injury Lawyer
Are you confused about what happened to your child? Miller & Zois can help. Call us at 800-553-8082. You will speak with a nurse attorney who will understand what has happened to you. We will explain your compensation options and answer any questions you may have. You can also get an online case review.